Lewis Structure of Oxygen

Oxygen
Lewis structure of oxygen

Preparation of Oxygen
a. Thermal decomposition of potassium chlorate(V)

2 KClO3 ( s )  2 KCl ( s ) + 3O2 ( g ) →
Drying agent: CaCl2, CaO, concentrated H2SO4

heat ,300ο C MnO2

b. Catalytic decomposition of hydrogen peroxide solution

2 H 2O2 (aq)  2 H 2O(l ) + O2 ( g ) →
c. Reaction between sodium peroxide and water 2Na2O2(s) + 2 H2O (l) → 4NaOH (aq) + O2 (aq)

MnO2

Other substances that produce O2
2 F2 ( g ) + 2 H 2O(l )  4 HF (aq) + 2O2 ( g ) → 2 HClO(aq) → 2 HCl (aq) + O2 ( g )
heat 2 KNO3 ( s ) → 2 KNO2 ( s ) + O2 ( g )  sunlight

2 AgNO3 ( s ) → 2 Ag ( s ) + 2 NO2 ( g ) + O2 ( g ) 

heat

Industrial Preparation
a. electrolysis of water and molten sodium hydroxide .
2 H 2 O ( l )  electro lysis → H 2 ( g ) + O 2 ( g )  2 N a O H ( l )  electro lysis → 2 N a ( s ) + H 2 ( g ) + O 2 ( g ) 

b. fractional distillation of liquid air.

Physical Properties
• • • • Oxygen is a diatomic gas. colorless, odorless and tasteless neutral to moist litmus paper. slightly soluble in water, i.e. only about 2% by volume of it will dissolve at room temperature. • denser than air. • Gaseous oxygen liquefies at −183°C (b.p) and solidifies at −225°C (m.p)

Chemical Properties
• very reactive. • combines readily with all other elements (except the noble gases, some halogens and some un-reactive metals) to form oxides.

Reaction with metals
• Many metals react with oxygen to form basic oxides(contains the O2- ion). • Example: • 2 Cu (s) + O2 (g) → 2 CuO (s) • 2 Mg (s) + O2 (g) → 2MgO(s)

Reaction between alkali metals and oxygen
• The basic oxide is not formed when sodium or potassium is heated in a plentiful supply of oxygen. − • Metal peroxides (contains O22− ion) are formed. • Sodium burns with a bright yellow flame to form sodium peroxide, Na2O2. 2Na(s) + O2 (g) → Na2O2(s) (sodium peroxide) Oxidation state of oxygen in peroxides is −1.

superoxides
• Very reactive...